Multi-gate radio frequency switches

ABSTRACT

Apparatus and methods for multi-gate radio frequency (RF) switches are disclosed herein. The RF switches use various layout design techniques to improve figure of merit (FOM). Examples of such techniques include using only two field-effect transistors (FETs) in series to maintain shorter fingers for lower metal resistance, placing a body contact on only one side of the RF switch layout, implementing metallization with reduced coupling from input to output, and/or providing air gaps to improve high frequency performance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 ofU.S. Provisional Patent Application No. 63/369,435, filed Jul. 26, 2022and titled “MULTI-GATE RADIO FREQUENCY SWITCHES,” and of U.S.Provisional Patent Application No. 63/369,439, filed Jul. 26, 2022 andtitled “APPARATUS AND METHODS FOR RADIO FREQUENCY SWITCHING,” each ofwhich is herein incorporated by reference in its entirety.

BACKGROUND Technical Field

Embodiments of the invention relate to electronic systems, and inparticular, to radio frequency (RF) electronics.

Description of Related Technology

Radio frequency (RF) communication systems can be used for transmittingand/or receiving signals of a wide range of frequencies. For example, anRF communication system can be used to wirelessly communicate RF signalsin a frequency range of about 30 kHz to 300 GHz, such as in the range ofabout 400 MHz to about 7.125 GHz for Frequency Range 1 (FR1) of theFifth Generation (5G) communication standard or in the range of about24.250 GHz to about 71.000 GHz for Frequency Range 2 (FR2) of the 5Gcommunication standard.

Examples of RF communication systems include, but are not limited to,mobile phones, tablets, base stations, network access points,customer-premises equipment (CPE), laptops, and wearable electronics.

SUMMARY

In certain embodiments, the present disclosure relates to a radiofrequency switch. The radio frequency switch includes a first transistorgate structure including a first gate connection extending in parallelwith a first edge of an active region and a first transistor gateextending from the first gate connection over the first edge of theactive region. The radio frequency switch further includes a secondtransistor gate structure including a second gate connection extendingin parallel with a second edge of the active region opposite the firstedge and a second transistor gate extending from the second gateconnection over the second edge of the active region. The radiofrequency switch further includes a radio frequency switch inputincluding a first source/drain connection extending in parallel to thefirst transistor gate and contacting the active region, and a radiofrequency switch output including a second source/drain connectionextending in parallel to the second transistor gate and contacting theactive region. The first transistor gate and the second transistor gateare positioned between the first source/drain connection and the secondsource/drain connection.

In some embodiments, the first source/drain connection does not reachthe second edge of the active region, and the second source/drainconnection does not reach the first edge of the active region.

In various embodiments, the first gate connection, the first transistorgate, the second gate connection, and the second transistor gate areformed of polysilicon.

In several embodiments, the active region is rectangular.

In a number of embodiments, the active region includes a firstrectangular region and a second rectangular region, the firstrectangular region abutting but offset from the second rectangularregion. According to various embodiments, the first transistor gateextends over the first rectangular region, and the second transistorgate extends over the second rectangular region.

In several embodiments, the radio frequency switch further includes aninternal drain/source bias region extending in parallel to the secondedge of the active region, the internal drain/source bias regioncontacting the active region between the first transistor gate and thesecond transistor gate.

In various embodiments, the active region is formed in a semiconductor,and the radio frequency switch further includes a body contact regionthat contacts the semiconductor adjacent to the first edge of the activeregion. According to a number of embodiments, the body contact regionincludes a plurality of body contacts bridged by metal. In accordancewith several embodiments, a body contact is present only on one side ofthe active region.

In certain embodiments, the present disclosure relates to a mobiledevice. The mobile device includes an antenna, and a front-end systemcoupled to the antenna and including a radio frequency switch. The radiofrequency switch includes a first transistor gate structure thatincludes a first gate connection extending in parallel with a first edgeof an active region and a first transistor gate extending from the firstgate connection over the first edge of the active region. The radiofrequency switch further incudes a second transistor gate structure thatincludes a second gate connection extending in parallel with a secondedge of the active region opposite the first edge and a secondtransistor gate extending from the second gate connection over thesecond edge of the active region. The radio frequency switch furtherincludes a radio frequency switch input that includes a firstsource/drain connection extending in parallel to the first transistorgate and contacting the active region, and a radio frequency switchoutput that includes a second source/drain connection extending inparallel to the second transistor gate and contacting the active region.The first transistor gate and the second transistor gate are positionedbetween the first source/drain connection and the second source/drainconnection.

In various embodiments, the front-end system further includes a poweramplifier having an output connected to the radio frequency switchinput.

In several embodiments, the front-end system further includes a lownoise amplifier having an input connected to the radio frequency switchoutput.

In certain embodiments, the present disclosure relates to a packagedmodule. The packaged module includes a package substrate and asemiconductor die attached to the package substrate and including aradio frequency switch formed thereon. The radio frequency switchincludes a first transistor gate structure that includes a first gateconnection extending in parallel with a first edge of an active regionand a first transistor gate extending from the first gate connectionover the first edge of the active region. The radio frequency switchfurther includes a second transistor gate structure that includes asecond gate connection extending in parallel with a second edge of theactive region opposite the first edge and a second transistor gateextending from the second gate connection over the second edge of theactive region. The radio frequency switch further includes a radiofrequency switch input that includes a first source/drain connectionextending in parallel to the first transistor gate and contacting theactive region, and a radio frequency switch output that includes asecond source/drain connection extending in parallel to the secondtransistor gate and contacting the active region. The first transistorgate and the second transistor gate are positioned between the firstsource/drain connection and the second source/drain connection.

In some embodiments, the first source/drain connection does not reachthe second edge of the active region, and the second source/drainconnection does not reach the first edge of the active region.

In several embodiments, the first gate connection, the first transistorgate, the second gate connection, and the second transistor gate areformed of polysilicon.

In some embodiments, the active region is rectangular.

In various embodiments, the active region includes a first rectangularregion and a second rectangular region, the first rectangular regionabutting but offset from the second rectangular region. According to anumber of embodiments, the first transistor gate extends over the firstrectangular region, and the second transistor gate extends over thesecond rectangular region. In accordance with several embodiments, thepackaged module further includes an internal drain/source bias regionextending in parallel to the second edge of the active region, theinternal drain/source bias region contacting the active region betweenthe first transistor gate and the second transistor gate.

In some embodiments, the semiconductor die includes a semiconductorregion in which the active region is formed, and the radio frequencyswitch further includes a body contact region that contacts thesemiconductor adjacent to the first edge of the active region.

In several embodiments, the body contact region includes a plurality ofbody contacts bridged by metal.

In various embodiments, a body contact is present only on one side ofthe active region.

In certain embodiments, a radio frequency switch is disclosed. The radiofrequency switch includes a first field-effect transistor including afirst source, a first drain, and a first transistor gate extending overa first edge of an active region. The radio frequency switch furtherincludes a second field-effect transistor having a second sourceconnected to the first drain, a second drain, and a second transistorgate extending over a second edge of the active region opposite thefirst edge. The radio frequency switch further includes a radiofrequency switch input connection extending in parallel to the firsttransistor gate and contacting the active region to connect to the firstsource of the first field-effect transistor. The radio frequency switchfurther includes a radio frequency switch output connection extending inparallel to the second transistor gate and contacting the active regionto connect to the second drain of the second field-effect transistor.The first transistor gate and the second transistor gate are positionedbetween the radio frequency switch input connection and the radiofrequency switch output connection.

In various embodiments, the radio frequency switch input connection doesnot reach the second edge of the active region, and the radio frequencyswitch output connection does not reach the first edge of the activeregion.

In several embodiments, the active region is rectangular.

In some embodiments, the active region includes a first rectangularregion and a second rectangular region, the first rectangular regionabutting but offset from the second rectangular region. According to anumber of embodiments, the first transistor gate extends over the firstrectangular region, and the second transistor gate extends over thesecond rectangular region.

In several embodiments, the radio frequency switch further includes aninternal drain/source bias region extending in parallel to the secondedge of the active region, the internal drain/source bias regioncontacting the active region to connect to the drain of the firstfield-effect transistor and to the source of the second field-effecttransistor.

In various embodiments, the active region is formed in a semiconductor,and the radio frequency switch further includes a body contact regionthat contacts the semiconductor adjacent to the first edge of the activeregion.

In some embodiments, the body contact region includes a plurality ofbody contacts bridged by metal. According to several embodiments, a bodycontact is present only on one side of the active region.

In certain embodiments, the present disclosure relates to a mobiledevice. The mobile device includes an antenna, and a front-end systemcoupled to the antenna and including a radio frequency switch. The radiofrequency switch includes a first field-effect transistor that includesa first source, a first drain, and a first transistor gate extendingover a first edge of an active region. The radio frequency switchfurther includes a second field-effect transistor that includes a secondsource connected to the first drain, a second drain, and a secondtransistor gate extending over a second edge of the active regionopposite the first edge. The radio frequency switch further includes aradio frequency switch input connection extending in parallel to thefirst transistor gate and contacting the active region to connect to thefirst source of the first field-effect transistor. The radio frequencyswitch further includes a radio frequency switch output connectionextending in parallel to the second transistor gate and contacting theactive region to connect to the second drain of the second field-effecttransistor. The first transistor gate and the second transistor gate arepositioned between the radio frequency switch input connection and theradio frequency switch output connection.

In various embodiments, the front-end system further includes a poweramplifier having an output connected to the radio frequency switchinput.

In several embodiments, the front-end system further includes a lownoise amplifier having an input connected to the radio frequency switchoutput.

In certain embodiments, the present disclosure relates to a packagedmodule. The packaged module includes a package substrate, and asemiconductor die attached to the package substrate and including aradio frequency switch formed thereon. The radio frequency switchincludes a first field-effect transistor that includes a first source, afirst drain, and a first transistor gate extending over a first edge ofan active region. The radio frequency switch further includes a secondfield-effect transistor that includes a second source connected to thefirst drain, a second drain, and a second transistor gate extending overa second edge of the active region opposite the first edge. The radiofrequency switch further includes a radio frequency switch inputconnection extending in parallel to the first transistor gate andcontacting the active region to connect to the first source of the firstfield-effect transistor. The radio frequency switch further includes aradio frequency switch output connection extending in parallel to thesecond transistor gate and contacting the active region to connect tothe second drain of the second field-effect transistor. The firsttransistor gate and the second transistor gate are positioned betweenthe radio frequency switch input connection and the radio frequencyswitch output connection.

In various embodiments, the radio frequency switch input connection doesnot reach the second edge of the active region, and the radio frequencyswitch output connection does not reach the first edge of the activeregion.

In several embodiments, the active region is rectangular.

In some embodiments, the active region includes a first rectangularregion and a second rectangular region, the first rectangular regionabutting but offset from the second rectangular region. According to anumber of embodiments, the first transistor gate extends over the firstrectangular region, and the second transistor gate extends over thesecond rectangular region.

In various embodiments, the packaged module further includes an internaldrain/source bias region extending in parallel to the second edge of theactive region, the internal drain/source bias region contacting theactive region to connect to the drain of the first field-effecttransistor and to the source of the second field-effect transistor.

In several embodiments, the active region is formed in a semiconductor,and the radio frequency switch further includes a body contact regionthat contacts the semiconductor adjacent to the first edge of the activeregion.

In some embodiments, the body contact region includes a plurality ofbody contacts bridged by metal. According to a number of embodiments, abody contact is present only on one side of the active region.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of this disclosure will now be described, by way ofnon-limiting example, with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of one example of a communication network.

FIG. 2A is a schematic diagram of one example of a communication linkusing carrier aggregation.

FIG. 2B illustrates various examples of uplink carrier aggregation forthe communication link of FIG. 2A.

FIG. 2C illustrates various examples of downlink carrier aggregation forthe communication link of FIG. 2A.

FIG. 3A is a schematic diagram of one example of a downlink channelusing multi-input and multi-output (MIMO) communications.

FIG. 3B is schematic diagram of one example of an uplink channel usingMIMO communications.

FIG. 3C is schematic diagram of another example of an uplink channelusing MIMO communications.

FIG. 4A is a schematic diagram of one example of a communication systemthat operates with beamforming.

FIG. 4B is a schematic diagram of one example of beamforming to providea transmit beam.

FIG. 4C is a schematic diagram of one example of beamforming to providea receive beam.

FIG. 5A is a schematic diagram of one embodiment of a layout for a radiofrequency (RF) switch.

FIG. 5B is a schematic diagram of another embodiment of a layout for anRF switch.

FIG. 5C is a schematic diagram of another embodiment of a layout for anRF switch.

FIG. 5D is a schematic diagram of another embodiment of a layout for anRF switch.

FIG. 5E is a schematic diagram of another embodiment of a layout for anRF switch.

FIG. 5F is a schematic diagram of another embodiment of a layout for anRF switch.

FIG. 5G is a schematic diagram of another embodiment of a layout for anRF switch.

FIG. 5H is a schematic diagram of another embodiment of a layout for anRF switch.

FIG. 5I is a schematic diagram of another embodiment of a layout for anRF switch.

FIG. 5J is a schematic diagram of another embodiment of a layout for anRF switch.

FIG. 6A is a graph of one example of on resistance versus frequency.

FIG. 6B is a graph of another example of on resistance versus frequency.

FIG. 7A is a schematic diagram of one embodiment of an RF switch.

FIG. 7B is a schematic diagram of another embodiment of an RF switch.

FIG. 7C is a schematic diagram of another embodiment of an RF switch.

FIG. 7D is a schematic diagram of one embodiment of a front-end system.

FIG. 8 is a schematic diagram of one embodiment of a mobile device.

FIG. 9 is a schematic diagram of a power amplifier system according toone embodiment.

FIG. 10A is a schematic diagram of one embodiment of a packaged module.

FIG. 10B is a schematic diagram of a cross-section of the packagedmodule of FIG. 10A taken along the lines 10B-10B.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following detailed description of certain embodiments presentsvarious descriptions of specific embodiments. However, the innovationsdescribed herein can be embodied in a multitude of different ways, forexample, as defined and covered by the claims. In this description,reference is made to the drawings where like reference numerals canindicate identical or functionally similar elements. It will beunderstood that elements illustrated in the figures are not necessarilydrawn to scale. Moreover, it will be understood that certain embodimentscan include more elements than illustrated in a drawing and/or a subsetof the elements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

The International Telecommunication Union (ITU) is a specialized agencyof the United Nations (UN) responsible for global issues concerninginformation and communication technologies, including the shared globaluse of radio spectrum.

The 3rd Generation Partnership Project (3GPP) is a collaboration betweengroups of telecommunications standard bodies across the world, such asthe Association of Radio Industries and Businesses (ARIB), theTelecommunications Technology Committee (TTC), the China CommunicationsStandards Association (CCSA), the Alliance for TelecommunicationsIndustry Solutions (ATIS), the Telecommunications Technology Association(TTA), the European Telecommunications Standards Institute (ETSI), andthe Telecommunications Standards Development Society, India (TSDSI).

Working within the scope of the ITU, 3GPP develops and maintainstechnical specifications for a variety of mobile communicationtechnologies, including, for example, second generation (2G) technology(for instance, Global System for Mobile Communications (GSM) andEnhanced Data Rates for GSM Evolution (EDGE)), third generation (3G)technology (for instance, Universal Mobile Telecommunications System(UMTS) and High Speed Packet Access (HSPA)), and fourth generation (4G)technology (for instance, Long Term Evolution (LTE) and LTE-Advanced).

The technical specifications controlled by 3GPP can be expanded andrevised by specification releases, which can span multiple years andspecify a breadth of new features and evolutions.

In one example, 3GPP introduced carrier aggregation (CA) for LTE inRelease 10. Although initially introduced with two downlink carriers,3GPP expanded carrier aggregation in Release 14 to include up to fivedownlink carriers and up to three uplink carriers. Other examples of newfeatures and evolutions provided by 3GPP releases include, but are notlimited to, License Assisted Access (LAA), enhanced LAA (eLAA),Narrowband Internet of things (NB-IOT), Vehicle-to-Everything (V2X), andHigh Power User Equipment (HPUE).

3GPP introduced Phase 1 of fifth generation (5G) technology in Release15, and introduced Phase 2 of 5G technology in Release 16. Subsequent3GPP releases will further evolve and expand 5G technology. 5Gtechnology is also referred to herein as 5G New Radio (NR).

5G NR supports or plans to support a variety of features, such ascommunications over millimeter wave spectrum, beamforming capability,high spectral efficiency waveforms, low latency communications, multipleradio numerology, and/or non-orthogonal multiple access (NOMA). Althoughsuch RF functionalities offer flexibility to networks and enhance userdata rates, supporting such features can pose a number of technicalchallenges.

The teachings herein are applicable to a wide variety of communicationsystems, including, but not limited to, communication systems usingadvanced cellular technologies, such as LTE-Advanced, LTE-Advanced Pro,and/or 5G NR.

FIG. 1 is a schematic diagram of one example of a communication network10. The communication network 10 includes a macro cell base station 1, asmall cell base station 3, and various examples of user equipment (UE),including a first mobile device 2 a, a wireless-connected car 2 b, alaptop 2 c, a stationary wireless device 2 d, a wireless-connected train2 e, a second mobile device 2 f, and a third mobile device 2 g.

Although specific examples of base stations and user equipment areillustrated in FIG. 1 , a communication network can include basestations and user equipment of a wide variety of types and/or numbers.

For instance, in the example shown, the communication network 10includes the macro cell base station 1 and the small cell base station3. The small cell base station 3 can operate with relatively lowerpower, shorter range, and/or with fewer concurrent users relative to themacro cell base station 1. The small cell base station 3 can also bereferred to as a femtocell, a picocell, or a microcell. Although thecommunication network 10 is illustrated as including two base stations,the communication network 10 can be implemented to include more or fewerbase stations and/or base stations of other types.

Although various examples of user equipment are shown, the teachingsherein are applicable to a wide variety of user equipment, including,but not limited to, mobile phones, tablets, laptops, IoT devices,wearable electronics, customer premises equipment (CPE),wireless-connected vehicles, wireless relays, and/or a wide variety ofother communication devices. Furthermore, user equipment includes notonly currently available communication devices that operate in acellular network, but also subsequently developed communication devicesthat will be readily implementable with the inventive systems,processes, methods, and devices as described and claimed herein.

The illustrated communication network 10 of FIG. 1 supportscommunications using a variety of cellular technologies, including, forexample, 4G LTE and 5G NR. In certain implementations, the communicationnetwork 10 is further adapted to provide a wireless local area network(WLAN), such as WiFi. Although various examples of communicationtechnologies have been provided, the communication network 10 can beadapted to support a wide variety of communication technologies.

Various communication links of the communication network 10 have beendepicted in FIG. 1 . The communication links can be duplexed in a widevariety of ways, including, for example, using frequency-divisionduplexing (FDD) and/or time-division duplexing (TDD). FDD is a type ofradio frequency communications that uses different frequencies fortransmitting and receiving signals. FDD can provide a number ofadvantages, such as high data rates and low latency. In contrast, TDD isa type of radio frequency communications that uses about the samefrequency for transmitting and receiving signals, and in which transmitand receive communications are switched in time. TDD can provide anumber of advantages, such as efficient use of spectrum and variableallocation of throughput between transmit and receive directions.

In certain implementations, user equipment can communicate with a basestation using one or more of 4G LTE, 5G NR, and WiFi technologies. Incertain implementations, enhanced license assisted access (eLAA) is usedto aggregate one or more licensed frequency carriers (for instance,licensed 4G LTE and/or 5G NR frequencies), with one or more unlicensedcarriers (for instance, unlicensed WiFi frequencies).

As shown in FIG. 1 , the communication links include not onlycommunication links between UE and base stations, but also UE to UEcommunications and base station to base station communications. Forexample, the communication network 10 can be implemented to supportself-fronthaul and/or self-backhaul (for instance, as between mobiledevice 2 g and mobile device 2 f).

The communication links can operate over a wide variety of frequencies.In certain implementations, communications are supported using 5G NRtechnology over one or more frequency bands that are less than 6Gigahertz (GHz) and/or over one or more frequency bands that are greaterthan 6 GHz. For example, the communication links can serve FrequencyRange 1 (FR1), Frequency Range 2 (FR2), or a combination thereof. In oneembodiment, one or more of the mobile devices support a HPUE power classspecification.

In certain implementations, a base station and/or user equipmentcommunicates using beamforming. For example, beamforming can be used tofocus signal strength to overcome path losses, such as high lossassociated with communicating over high signal frequencies. In certainembodiments, user equipment, such as one or more mobile phones,communicate using beamforming on millimeter wave frequency bands in therange of 30 GHz to 300 GHz and/or upper centimeter wave frequencies inthe range of 6 GHz to 30 GHz, or more particularly, 24 GHz to 30 GHz.Cellular user equipment can communicate using beamforming and/or othertechniques over a wide range of frequencies, including, for example,FR2-1 (24 GHz to 52 GHz), FR2-2 (52 GHz to 71 GHz), and/or FR1 (400 MHzto 7125 MHz).

Different users of the communication network 10 can share availablenetwork resources, such as available frequency spectrum, in a widevariety of ways.

In one example, frequency division multiple access (FDMA) is used todivide a frequency band into multiple frequency carriers. Additionally,one or more carriers are allocated to a particular user. Examples ofFDMA include, but are not limited to, single carrier FDMA (SC-FDMA) andorthogonal FDMA (OFDMA). OFDMA is a multicarrier technology thatsubdivides the available bandwidth into multiple mutually orthogonalnarrowband subcarriers, which can be separately assigned to differentusers.

Other examples of shared access include, but are not limited to, timedivision multiple access (TDMA) in which a user is allocated particulartime slots for using a frequency resource, code division multiple access(CDMA) in which a frequency resource is shared amongst different usersby assigning each user a unique code, space-divisional multiple access(SDMA) in which beamforming is used to provide shared access by spatialdivision, and non-orthogonal multiple access (NOMA) in which the powerdomain is used for multiple access. For example, NOMA can be used toserve multiple users at the same frequency, time, and/or code, but withdifferent power levels.

Enhanced mobile broadband (eMBB) refers to technology for growing systemcapacity of LTE networks. For example, eMBB can refer to communicationswith a peak data rate of at least 10 Gbps and a minimum of 100 Mbps foreach user. Ultra-reliable low latency communications (uRLLC) refers totechnology for communication with very low latency, for instance, lessthan 2 milliseconds. uRLLC can be used for mission-criticalcommunications such as for autonomous driving and/or remote surgeryapplications. Massive machine-type communications (mMTC) refers to lowcost and low data rate communications associated with wirelessconnections to everyday objects, such as those associated with Internetof Things (IoT) applications.

The communication network 10 of FIG. 1 can be used to support a widevariety of advanced communication features, including, but not limitedto, eMBB, uRLLC, and/or mMTC.

FIG. 2A is a schematic diagram of one example of a communication linkusing carrier aggregation. Carrier aggregation can be used to widenbandwidth of the communication link by supporting communications overmultiple frequency carriers, thereby increasing user data rates andenhancing network capacity by utilizing fragmented spectrum allocations.

In the illustrated example, the communication link is provided between abase station 21 and a mobile device 22. As shown in FIG. 2A, thecommunications link includes a downlink channel used for RFcommunications from the base station 21 to the mobile device 22, and anuplink channel used for RF communications from the mobile device 22 tothe base station 21.

Although FIG. 2A illustrates carrier aggregation in the context of FDDcommunications, carrier aggregation can also be used for TDDcommunications.

In certain implementations, a communication link can provideasymmetrical data rates for a downlink channel and an uplink channel.For example, a communication link can be used to support a relativelyhigh downlink data rate to enable high speed streaming of multimediacontent to a mobile device, while providing a relatively slower datarate for uploading data from the mobile device to the cloud.

In the illustrated example, the base station 21 and the mobile device 22communicate via carrier aggregation, which can be used to selectivelyincrease bandwidth of the communication link. Carrier aggregationincludes contiguous aggregation, in which contiguous carriers within thesame operating frequency band are aggregated. Carrier aggregation canalso be non-contiguous, and can include carriers separated in frequencywithin a common band or in different bands.

In the example shown in FIG. 2A, the uplink channel includes threeaggregated component carriers f_(UL1), f_(UL2), and f_(UL3).Additionally, the downlink channel includes five aggregated componentcarriers f_(DL1), f_(DL2), f_(DL3), f_(DL4), and f_(DL5). Although oneexample of component carrier aggregation is shown, more or fewercarriers can be aggregated for uplink and/or downlink. Moreover, anumber of aggregated carriers can be varied over time to achieve desireduplink and downlink data rates.

For example, a number of aggregated carriers for uplink and/or downlinkcommunications with respect to a particular mobile device can changeover time. For example, the number of aggregated carriers can change asthe device moves through the communication network and/or as networkusage changes over time.

FIG. 2B illustrates various examples of uplink carrier aggregation forthe communication link of FIG. 2A. FIG. 2B includes a first carrieraggregation scenario 31, a second carrier aggregation scenario 32, and athird carrier aggregation scenario 33, which schematically depict threetypes of carrier aggregation.

The carrier aggregation scenarios 31-33 illustrate different spectrumallocations for a first component carrier f_(UL1), a second componentcarrier f_(UL2), and a third component carrier f_(UL3). Although FIG. 2Bis illustrated in the context of aggregating three component carriers,carrier aggregation can be used to aggregate more or fewer carriers.Moreover, although illustrated in the context of uplink, the aggregationscenarios are also applicable to downlink.

The first carrier aggregation scenario 31 illustrates intra-bandcontiguous carrier aggregation, in which component carriers that areadjacent in frequency and in a common frequency band are aggregated. Forexample, the first carrier aggregation scenario 31 depicts aggregationof component carriers f_(UL1), f_(UL2), and f_(UL3) that are contiguousand located within a first frequency band BAND1.

With continuing reference to FIG. 2B, the second carrier aggregationscenario 32 illustrates intra-band non-continuous carrier aggregation,in which two or more components carriers that are non-adjacent infrequency and within a common frequency band are aggregated. Forexample, the second carrier aggregation scenario 32 depicts aggregationof component carriers f_(UL1), f_(UL2), and f_(UL3) that arenon-contiguous, but located within a first frequency band BAND1.

The third carrier aggregation scenario 33 illustrates inter-bandnon-contiguous carrier aggregation, in which component carriers that arenon-adjacent in frequency and in multiple frequency bands areaggregated. For example, the third carrier aggregation scenario 33depicts aggregation of component carriers f_(UL1) and f_(UL2) of a firstfrequency band BAND1 with component carrier f_(UL3) of a secondfrequency band BAND2.

FIG. 2C illustrates various examples of downlink carrier aggregation forthe communication link of FIG. 2A. The examples depict various carrieraggregation scenarios 34-38 for different spectrum allocations of afirst component carrier f_(DL1), a second component carrier f_(DL2), athird component carrier f_(DL3), a fourth component carrier f_(DL4), anda fifth component carrier f_(DL5). Although FIG. 2C is illustrated inthe context of aggregating five component carriers, carrier aggregationcan be used to aggregate more or fewer carriers. Moreover, althoughillustrated in the context of downlink, the aggregation scenarios arealso applicable to uplink.

The first carrier aggregation scenario 34 depicts aggregation ofcomponent carriers that are contiguous and located within the samefrequency band. Additionally, the second carrier aggregation scenario 35and the third carrier aggregation scenario 36 illustrates two examplesof aggregation that are non-contiguous but located within the samefrequency band. Furthermore, the fourth carrier aggregation scenario 37and the fifth carrier aggregation scenario 38 illustrates two examplesof aggregation in which component carriers that are non-adjacent infrequency and in multiple frequency bands are aggregated. As a number ofaggregated component carriers increases, a complexity of possiblecarrier aggregation scenarios also increases.

With reference to FIGS. 2A-2C, the individual component carriers used incarrier aggregation can be of a variety of frequencies, including, forexample, frequency carriers in the same band or in multiple bands.Additionally, carrier aggregation is applicable to implementations inwhich the individual component carriers are of about the same bandwidthas well as to implementations in which the individual component carriershave different bandwidths.

Certain communication networks allocate a particular user device with aprimary component carrier (PCC) or anchor carrier for uplink and a PCCfor downlink. Additionally, when the mobile device communicates using asingle frequency carrier for uplink or downlink, the user devicecommunicates using the PCC. To enhance bandwidth for uplinkcommunications, the uplink PCC can be aggregated with one or more uplinksecondary component carriers (SCCs). Additionally, to enhance bandwidthfor downlink communications, the downlink PCC can be aggregated with oneor more downlink SCCs.

In certain implementations, a communication network provides a networkcell for each component carrier. Additionally, a primary cell canoperate using a PCC, while a secondary cell can operate using a SCC. Theprimary and secondary cells may have different coverage areas, forinstance, due to differences in frequencies of carriers and/or networkenvironment.

License assisted access (LAA) refers to downlink carrier aggregation inwhich a licensed frequency carrier associated with a mobile operator isaggregated with a frequency carrier in unlicensed spectrum, such asWiFi. LAA employs a downlink PCC in the licensed spectrum that carriescontrol and signaling information associated with the communicationlink, while unlicensed spectrum is aggregated for wider downlinkbandwidth when available. LAA can operate with dynamic adjustment ofsecondary carriers to avoid WiFi users and/or to coexist with WiFiusers. Enhanced license assisted access (eLAA) refers to an evolution ofLAA that aggregates licensed and unlicensed spectrum for both downlinkand uplink. Furthermore, NR-U can operate on top of LAA/eLAA over a 5GHz band (5150 to 5925 MHz) and/or a 6 GHz band (5925 MHz to 7125 MHz).

FIG. 3A is a schematic diagram of one example of a downlink channelusing multi-input and multi-output (MIMO) communications. FIG. 3B isschematic diagram of one example of an uplink channel using MIMOcommunications.

MIMO communications use multiple antennas for simultaneouslycommunicating multiple data streams over common frequency spectrum. Incertain implementations, the data streams operate with differentreference signals to enhance data reception at the receiver. MIMOcommunications benefit from higher SNR, improved coding, and/or reducedsignal interference due to spatial multiplexing differences of the radioenvironment.

MIMO order refers to a number of separate data streams sent or received.For instance, MIMO order for downlink communications can be described bya number of transmit antennas of a base station and a number of receiveantennas for UE, such as a mobile device. For example, two-by-two (2×2)DL MIMO refers to MIMO downlink communications using two base stationantennas and two UE antennas. Additionally, four-by-four (4×4) DL MIMOrefers to MIMO downlink communications using four base station antennasand four UE antennas.

In the example shown in FIG. 3A, downlink MIMO communications areprovided by transmitting using M antennas 43 a, 43 b, 43 c, . . . 43 mof the base station 41 and receiving using N antennas 44 a, 44 b, 44 c,. . . 44 n of the mobile device 42. Accordingly, FIG. 3A illustrates anexample of m×n DL MIMO.

Likewise, MIMO order for uplink communications can be described by anumber of transmit antennas of UE, such as a mobile device, and a numberof receive antennas of a base station. For example, 2×2 UL MIMO refersto MIMO uplink communications using two UE antennas and two base stationantennas. Additionally, 4×4 UL MIMO refers to MIMO uplink communicationsusing four UE antennas and four base station antennas.

In the example shown in FIG. 3B, uplink MIMO communications are providedby transmitting using N antennas 44 a, 44 b, 44 c, . . . 44 n of themobile device 42 and receiving using M antennas 43 a, 43 b, 43 c, . . .43 m of the base station 41. Accordingly, FIG. 3B illustrates an exampleof n×m UL MIMO.

By increasing the level or order of MIMO, bandwidth of an uplink channeland/or a downlink channel can be increased.

MIMO communications are applicable to communication links of a varietyof types, such as FDD communication links and TDD communication links.

FIG. 3C is schematic diagram of another example of an uplink channelusing MIMO communications. In the example shown in FIG. 3C, uplink MIMOcommunications are provided by transmitting using N antennas 44 a, 44 b,44 c, . . . 44 n of the mobile device 42. Additional a first portion ofthe uplink transmissions are received using M antennas 43 a 1, 43 b 1,43 c 1, . . . 43 m 1 of a first base station 41 a, while a secondportion of the uplink transmissions are received using M antennas 43 a2, 43 b 2, 43 c 2, . . . 43 m 2 of a second base station 41 b.Additionally, the first base station 41 a and the second base station 41b communication with one another over wired, optical, and/or wirelesslinks.

The MIMO scenario of FIG. 3C illustrates an example in which multiplebase stations cooperate to facilitate MIMO communications.

FIG. 4A is a schematic diagram of one example of a communication system110 that operates with beamforming. The communication system 110includes a transceiver 105, signal conditioning circuits 104 a 1, 104 a2 . . . 104 an, 104 b 1, 104 b 2 . . . 104 bn, 104 m 1, 104 m 2 . . .104 mn, and an antenna array 102 that includes antenna elements 103 a 1,103 a 2 . . . 103 an, 103 b 1, 103 b 2 . . . 103 bn, 103 m 1, 103 m 2 .. . 103 mn.

Communications systems that communicate using millimeter wave carriers(for instance, 30 GHz to 300 GHz), centimeter wave carriers (forinstance, 3 GHz to 30 GHz), and/or other frequency carriers can employan antenna array to provide beam formation and directivity fortransmission and/or reception of signals.

For example, in the illustrated embodiment, the communication system 110includes an array 102 of m×n antenna elements, which are each controlledby a separate signal conditioning circuit, in this embodiment. Asindicated by the ellipses, the communication system 110 can beimplemented with any suitable number of antenna elements and signalconditioning circuits.

With respect to signal transmission, the signal conditioning circuitscan provide transmit signals to the antenna array 102 such that signalsradiated from the antenna elements combine using constructive anddestructive interference to generate an aggregate transmit signalexhibiting beam-like qualities with more signal strength propagating ina given direction away from the antenna array 102.

In the context of signal reception, the signal conditioning circuitsprocess the received signals (for instance, by separately controllingreceived signal phases) such that more signal energy is received whenthe signal is arriving at the antenna array 102 from a particulardirection. Accordingly, the communication system 110 also providesdirectivity for reception of signals.

The relative concentration of signal energy into a transmit beam or areceive beam can be enhanced by increasing the size of the array. Forexample, with more signal energy focused into a transmit beam, thesignal propagates for a longer range while providing sufficient signallevel for RF communications. For instance, a signal with a largeproportion of signal energy focused into the transmit beam can exhibithigh effective isotropic radiated power (EIRP).

In the illustrated embodiment, the transceiver 105 provides transmitsignals to the signal conditioning circuits and processes signalsreceived from the signal conditioning circuits. As shown in FIG. 4A, thetransceiver 105 generates control signals for the signal conditioningcircuits. The control signals can be used for a variety of functions,such as controlling the gain and phase of transmitted and/or receivedsignals to control beamforming.

FIG. 4B is a schematic diagram of one example of beamforming to providea transmit beam. FIG. 4B illustrates a portion of a communication systemincluding a first signal conditioning circuit 114 a, a second signalconditioning circuit 114 b, a first antenna element 113 a, and a secondantenna element 113 b.

Although illustrated as included two antenna elements and two signalconditioning circuits, a communication system can include additionalantenna elements and/or signal conditioning circuits. For example, FIG.4B illustrates one embodiment of a portion of the communication system110 of FIG. 4A.

The first signal conditioning circuit 114 a includes a first phaseshifter 130 a, a first power amplifier 131 a, a first low noiseamplifier (LNA) 132 a, and switches for controlling selection of thepower amplifier 131 a or LNA 132 a. Additionally, the second signalconditioning circuit 114 b includes a second phase shifter 130 b, asecond power amplifier 131 b, a second LNA 132 b, and switches forcontrolling selection of the power amplifier 131 b or LNA 132 b.

Although one embodiment of signal conditioning circuits is shown, otherimplementations of signal conditioning circuits are possible. Forinstance, in one example, a signal conditioning circuit includes one ormore band filters, duplexers, and/or other components.

In the illustrated embodiment, the first antenna element 113 a and thesecond antenna element 113 b are separated by a distance d.Additionally, FIG. 4B has been annotated with an angle Θ, which in thisexample has a value of about 90° when the transmit beam direction issubstantially perpendicular to a plane of the antenna array and a valueof about 0° when the transmit beam direction is substantially parallelto the plane of the antenna array.

By controlling the relative phase of the transmit signals provided tothe antenna elements 113 a, 113 b, a desired transmit beam angle Θ canbe achieved. For example, when the first phase shifter 130 a has areference value of 0°, the second phase shifter 130 b can be controlledto provide a phase shift of about −2πf(d/ν)cos Θ radians, where f is thefundamental frequency of the transmit signal, d is the distance betweenthe antenna elements, ν is the velocity of the radiated wave, and π isthe mathematic constant pi.

In certain implementations, the distance d is implemented to be about½λ, where λ is the wavelength of the fundamental component of thetransmit signal. In such implementations, the second phase shifter 130 bcan be controlled to provide a phase shift of about −π cos Θ radians toachieve a transmit beam angle Θ.

Accordingly, the relative phase of the phase shifters 130 a, 130 b canbe controlled to provide transmit beamforming. In certainimplementations, a baseband processor and/or a transceiver (for example,the transceiver 105 of FIG. 4A) controls phase values of one or morephase shifters and gain values of one or more controllable amplifiers tocontrol beamforming.

FIG. 4C is a schematic diagram of one example of beamforming to providea receive beam. FIG. 4C is similar to FIG. 4B, except that FIG. 4Cillustrates beamforming in the context of a receive beam rather than atransmit beam.

As shown in FIG. 4C, a relative phase difference between the first phaseshifter 130 a and the second phase shifter 130 b can be selected toabout equal to −2πf(d/ν)cos Θ radians to achieve a desired receive beamangle Θ. In implementations in which the distance d corresponds to about½λ), the phase difference can be selected to about equal to −π cos Θradians to achieve a receive beam angle Θ.

Although various equations for phase values to provide beamforming havebeen provided, other phase selection values are possible, such as phasevalues selected based on implementation of an antenna array,implementation of signal conditioning circuits, and/or a radioenvironment.

Examples of RF Switches

An overall performance of an RF communication system can be impacted bythe performance of RF switches along signal paths of the RFcommunication system.

One key figure of merit (FOM) of an RF switch is a product of theon-state resistance (Ron) and off-state capacitance (Coff) of the RFswitch. As operating frequencies increase (for example, to frequenciesof 20 GHz or more, such as 5G FR2 and/or millimeter wave frequencies),inductive and/or skin effects arising from a layout of the RF switchleads to a degradation in FOM.

A multi-gate layout can be used to reduce resistance contributions byremoving a portion of the metal routing and its associated resistance,inductance, and/or current crowding effects.

However, conventional multi-gate RF switches suffer from a number ofundesirable properties including, for example, direct input to outputmetal parasitics (for instance, coupling from an input metal bus to anoutput metal bus), long metal fingers that handle large currents,additional coupling from internal drain-to-source routing, and/or nobody bias (only floating body design). Such undesirable propertiesdegrade FOM.

Apparatus and methods for multi-gate RF switches are disclosed herein.The RF switches used a number of layout design techniques to improveFOM. For example, the RF switches can be implemented with variousfeatures to lower Ron and/or decrease Coff, thereby leading to animprovement in FOM.

In certain implementations, an RF switch layout includes only two FETsin series (two gates placed over a diffusion region between source anddrain contacts) to maintain shorter fingers for lower drain/source metalresistance. Additionally, using only two gates avoids directinput/output coupling otherwise present for a stack of 4 or more gates.Such RF switch layouts of two gates can be stacked to form a compositeRF switch including more than two gates. Thus, an RF switch with adesired number of gates can be achieved to realize a desired powerhandling capability.

The RF switch layouts herein can be implemented with a body bias. Forexample, a T-body style can be used to access the body of each FET.Although a floating body layout remains possible and can be morecompact.

In certain implementations, the body contact is placed on only one sideof the RF switch layout (for a first gate/first FET) with a secondgate/second FET on the other side omitting a body contact. Byimplementing the RF switch layout in this manner, gate routing throughpolysilicon (poly) can be achieved. Accordingly, FET to FET routing (inthe stack) is enabled, which allows a lowest metal layer (a first metallayer or metal one placed closest to active silicon) to be used forlower overall Ron. Furthermore, such benefits are achieved whileallowing for body bias.

The direct coupling from input to output can be reduced by making thedrain/source fingers shorter and removing the tip (removing, forinstance, or more contacts to the active region and associated metal).Thus, in certain implementations, metal is omitted at the end of a drainand/or source finger in favor of using silicide to distribute thecurrent to the end of the finger. Additionally or alternatively,input/output metal bars can be spaced away from output/inputdrain/source fingers.

In certain implementations, internal drain/source DC bias (between twogates) is achieved by relying on active silicide. Such active silicidecan use a meandering route (or snake routing) to avoid interruption ofmain input/output metal drain/source routing layers (for example, onmetal one or in other implementations, on metal one and metal two). Bybiasing the internal node, floating body effects such as slow settlingtimes and/or history effects are avoided.

The RF switch layouts herein can also push out the source/drain contactresistance away from the gate to reduce the drain/source metal couplingcapacitance and leveraging the low resistance of the drain/sourcesilicide. Such a technique can be applied to both side of the gates oronly on the side a metal connection is present. For example, by applyingthis technique to only the metal routing side, a better tradeoff betweenarea and Coff tradeoff may be achieved for some applications.

In certain implementations, air gap trenches between contacts and metalone are used to reduce coupling from metal one to metal one, fromcontact to contact, and/or from metal one to contact. Thus, air-gaptrenches between bias resistors can be used to improve performance athigher frequencies, such as FR2 frequencies.

FIG. 5A is a schematic diagram of one embodiment of a layout 150 for anRF switch. The layout 150 is formed in a semiconductor substrate 151,which can have any suitable doping. The layout 150 represents anoverhead or plan view of a cell for an RF switch. The layout 150includes an active region 152, a gate structure or gate 153, a switchinput 155, a switch output 156, and contacts 157 for providing aconnection from metal regions to the active region 152.

The active region 152 is rectangular, in this embodiment. Additionally,the gate structure 153 includes a first horizontal gate region 153 a 1along a bottom edge of the active region 152 and a second horizontalgate region 153 a 2 along a top edge of the active region 152.Additionally, the gate structure 153 includes a first vertical gateregion 153 b 1 and a second vertical gate region 153 b 2 connecting thefirst horizontal gate region 153 a 1 to the second horizontal gateregion 153 a 2.

As used herein, the terms horizontal and vertical serve to denote a pairof orthogonal directions (for instance, x and y) relative to anyreference point.

With continuing reference to FIG. 5A, the switch input 155 includes ahorizontal metal region 155 a, a first vertical metal region 155 b 1, asecond vertical metal region 155 b 2, and a third vertical metal region155 b 3. The vertical metal regions 155 b 1-155 b 3 extend upwardly fromthe horizontal metal region 155 a over the bottom edge of the activeregion 152 but do not reach the top edge of the active region 152.Contacts 157 are included along each of the vertical metal regions 155 b1-155 b 3 to contact the switch's source/drain regions. Thus, thecontacts 157 serve as an electrical connection between the verticalmetal regions and the active region 152.

The switch output 156 includes a horizontal metal region 156 a, a firstvertical metal region 156 b 1, and a second vertical metal region 156 b2. The vertical metal regions 156 b 1-156 b 2 extend downwardly from thehorizontal metal region 155 a over the top edge of the active region 152but do not reach the bottom edge of the active region 152. Contacts 157are included along each of the vertical metal regions 155 b 1-155 b 2 tocontact the switch's source/drain regions.

FIG. 5B is a schematic diagram of another embodiment of a layout 160 foran RF switch. The layout 160 includes an active region 152, a first gatestructure 163, a second gate structure 164, a switch input 165, a switchoutput 166, and contacts 157 for providing a connection from metalregions to the active region 152.

The first gate structure 163 includes a horizontal gate region 163 abelow a bottom edge of the active region 152. Additionally, the firstgate structure 163 includes a first vertical gate region 163 b 1, asecond vertical gate region 163 b 2, and a third vertical gate region163 b 3 extending upward from the horizontal gate region 163 a to a topedge of the active region 152.

With continuing reference to FIG. 5B, the second gate structure 164includes a horizontal gate region 164 above the top edge of the activeregion 152. Additionally, the second gate structure 164 includes a firstvertical gate region 143 b 1, a second vertical gate region 164 b 2, anda third vertical gate region 164 b 3 extending downward from thehorizontal gate region 164 a to the bottom edge of the active region152.

The switch input 165 includes a horizontal metal region 165 a, a firstvertical metal region 165 b 1, and a second vertical metal region 165 b2. The vertical metal regions 165 b 1-165 b 2 extend upwardly from thehorizontal metal region 165 a over the bottom edge of the active region152 but do not reach the top edge of the active region 152. Contacts 157are included along each of the vertical metal regions 165 b 1-165 b 2 tocontact the switch's source/drain regions.

The switch output 166 includes a horizontal metal region 166 a, a firstvertical metal region 166 b 1, and a second vertical metal region 166 b2. The vertical metal regions 166 b 1-166 b 2 extend downwardly from thehorizontal metal region 166 a over the top edge of the active region 152but do not reach the bottom edge of the active region 152. Contacts 157are included along each of the vertical metal regions 166 b 1-166 b 2 tocontact the switch's source/drain regions.

A first field-effect transistor (FET) M1 and a second FET M2 aredepicted in FIG. 5B. The first FET M1 and the second FET M2 are inseries between the switch input 165 and the switch output 166. Eachvertical region of the first gate structure 163 forms a finger of thefirst FET M1, while each vertical region of the second gate structure164 forms a finger of the second FET M2.

The horizontal gate region 163 a is made of polysilicon, and is used toprovide connections between the vertical gate regions 163 b 1-163 b 3that form the gate of M1. Thus, gate fingers are connected bypolysilicon rather than metal. Likewise, horizontal gate region 164 a ismade of polysilicon, and is used to provide connections between thevertical gate regions 164 b 1-164 b 3 that form the gate of M2.

The input and output of the dual-gate switch can use the lowest routinglayer (metal one) throughout for better Ron. For example, implementingthe switch in this manner avoids a need for an RF signal to propagatethrough resistive vias connecting metal layers. However, more metal canbe stacked on top of the depicted metal one regions to further reduceRon.

As shown in FIG. 5B, no contacts 157 are included between the verticalgate region 163 b 1 of the first gate structure 163 and the verticalgate region 164 b 1 of the second gate structure 164. Thus, an innerdrain/source region between M1 and M2 does not include contacts.Removing this metal reduces total parasitic capacitance.

FIG. 5C is a schematic diagram of another embodiment of a layout 170 foran RF switch. The layout 170 includes an active region 152, a first gatestructure 163, a second gate structure 164, a switch input 165, a switchoutput 166, and contacts 157 for providing a connection from metalregions to the active region 152.

The layout 170 of FIG. 5C is similar to the layout 160 of FIG. 5B.However, the layout 170 of FIG. 5C is annotated to show a separation 171between a tip of the vertical metal region 165 b 1 of the switch input165 and the top edge of the active region 152, and to a metal-to-metalspacing 172 between a tip of the vertical metal region 165 b 2 of theswitch input 165 and the horizontal metal region 166 a of the switchoutput 166.

By implementing the layout 170 in this manner, a low amount of parasiticcapacitance between the switch input 165 and the switch output 166 isprovided.

Accordingly, in certain implementations herein, a tip of a drain/sourcefinger is cut relative to an edge of an active region. Additionally oralternatively, an increased distance between the drain/source metalfinger tips and the input/output metal bar is provided. Thus, thecurrent is carried from the contacts to the FET channel through thesource/drain silicide.

FIG. 5D is a schematic diagram of another embodiment of a layout 180 foran RF switch. The layout 180 includes an active region 152, a first gatestructure 163, a second gate structure 164, a switch input 165, a switchoutput 166, contacts 157, a first body bias region 181, and a secondbody bias region 182.

The layout 180 of FIG. 5D is similar to the layout 170 of FIG. 5C,except that the layout 180 further includes the first body bias region181 for biasing the body of M1 and the second body bias region 182 forbiasing the body of M2. The body biasing regions 181 and 182 runhorizontally (orthogonally to the vertical gate regions serving as thegates of M1 and M2) in FIG. 5D.

With reference to FIG. 5D, the bodies of M1 and M2 can be accessed usinga T-gate style layout where the region under the gate remains p-type(for an NMOS) and can be connected to a p-type region outside the FET.By using only two gates for the multi-gate, a T-gate configuration canbe leveraged to access the body of transistors M1 and M2, each onerespectively biased on one side (top and bottom in FIG. 5D). An exampleof the T-gate biasing 183 for M1 is depicted in FIG. 5D.

FIG. 5E is a schematic diagram of another embodiment of a layout 190 foran RF switch. The layout 190 includes an active region 152, a first gatestructure 163, a second gate structure 164, a switch input 165, a switchoutput 166, contacts 157, first body bias segments 181 a/181 b, secondbody bias segments 182 a/182 b, a first body metal connection 191, and asecond body metal connection 192.

The layout 190 of FIG. 5E is similar to the layout 180 of FIG. 5D,except that the layout 190 of FIG. 5E partitions the first body regioninto body bias segments 181 a/181 b interconnected by the first bodymetal connection 191, and partitions the second body region into bodybias segments 182 a/182 b interconnected by the second body metalconnection 192.

To reduce the gate to body capacitance and the body to substratecapacitance, the layout can be implemented with body bias segments thatcan be small (for example, the minimum possible permitted by technologydesign rules) and interconnected by metal that joins the body contactsfor a particular transistor together.

FIG. 5F is a schematic diagram of another embodiment of a layout 200 foran RF switch. The layout 200 includes an active region 152, a first gatestructure 163, a second gate structure 164, a switch input 165, a switchoutput 166, contacts 157, via/contact stacks 207, a first upperdrain/source bias region 201 a, a second upper drain/source bias region201 b, a first lower drain/source bias region 202 a, and a second lowerdrain/source bias region 202 b.

The layout 200 of FIG. 5F is similar to the layout 170 of FIG. 5C,except that the layout 200 further includes the upper drain/source biasregions 201 a/201 b and the lower drain/source bias regions 202 a/202 b,which serve as bridges over the gates.

The drain/source bias regions run horizontally (orthogonally to thevertical gate regions serving as the gates of M1 and M2) in FIG. 5F.Additionally, the FETs M1 and M2 are connected in series between theswitch input 165 and the switch output 166, and the internalsource/drain node between M1 and M2 is biased by the drain/source biasregions.

Accordingly, the internal drain/source node is biased by adding bridgesbetween each sub-section in a snake pattern 157 to avoid intersectingwith the drain/source metal routing.

In certain implementations, the drain/source bias regions are formed insilicide. Bias can be applied and/or resistors can be connected to oneend or both ends of the snake to reduce the effective internalresistance from the silicide.

Although silicide can be used in some implementations, in otherimplementations drain/source bias regions are built in upper metal (forexample, metal two or metal three).

FIG. 5G is a schematic diagram of another embodiment of a layout 210 foran RF switch. The layout 210 includes an active region 152, a first gatestructure 163, a second gate structure 164, a switch input 165, a switchoutput 166, contacts 157, via/contact stacks 207, and a drain/sourcebias metal connection 211.

The layout 210 of FIG. 5G is similar to the layout 200 of FIG. 5F,except that the layout 210 includes the drain/source bias metalconnection 211 for biasing the internal drain/source node between M1 andM2.

In certain implementations, the drain/source bias metal connection 211includes one or more metal layers (for example, metal two and/or metalthree) connected by vias/contacts down to a silicide region.Additionally, overlapping of both the input and output metal traces canbe avoided to reduce Cds.

FIG. 5H is a schematic diagram of another embodiment of a layout 220 foran RF switch. The layout 220 includes an active region 152, a first gatestructure 163, a second gate structure 164′, a switch input 165′, aswitch output 166, contacts 157, via/contact stacks 207, and adrain/source bias metal connection 221.

The layout 220 of FIG. 5H is similar to the layout 210 of FIG. 5G,except that the layout 220 includes the drain/source bias metalconnection 221 for biasing the internal drain/source node between M1 andM2. The drain/source bias metal connection 221 of FIG. 5H is placed inthe middle of the FET structure (vertically centered between the switchinput and the switch output) to balance coupling to the RF input RFinand the RF output RFout. However, as a downside to the balancedcoupling, direct input to output coupling (by way of capacitancecoupling through the internal drain/source node) can increase.

In the embodiment of FIG. 5H, the switch input 165′ and the switchoutput 166′ also include additional upper metal to reduce gateresistivity.

FIG. 5I is a schematic diagram of another embodiment of a layout 230 foran RF switch. The layout 230 includes an active region 152, a first gatestructure 163, a second gate structure 164, a switch input 165, a switchoutput 166, contacts 157, via/contact stacks 207, first body biassegments 181 a/181 b, second body bias segments 182 a/182 b, a firstbody metal connection 191, a second body metal connection 192, a firstupper drain/source bias region 201 a, a second upper drain/source biasregion 201 b, a first lower drain/source bias region 202 a, a secondlower drain/source bias region 202 b, gate air gaps 231 a/231 b/231c/231 d/231 e/231 f (each positioned over a vertical gate regionsserving as a gate of M1 or M2), gate feed air gaps 232 a/232 b/232 c/232d/232 e/232 f (each positioned over a connection between a vertical gateregion and the horizontal gate region), and internal source/drain airgaps 233 a/233 b/233 c (each over the internal source/drain regionbetween M1 and M2).

By adding air gaps, parasitic coupling can be reduced. Such air gaps canbe implemented as trenches (filled with air) where metal has beenremoved between gates and/or outside of the active area where couplingto gate or body can occur.

FIG. 5J is a schematic diagram of another embodiment of a layout 240 foran RF switch. The layout includes an active region 152′, a first gatestructure 163, a second gate structure 164, a switch input 165, a switchoutput 166, contacts 157, via/contact stacks 207, a first body biasregion 181, a second body bias region 182, an upper drain/source biasregion 201, and a lower drain/source bias region 202.

As shown in FIG. 5J, the layout 240 includes the active region 152′,which includes first active regions 151 al/151 a 2 for M1 that areoffset from second active regions 151 b 1/151 b 2.

Accordingly, the layout 240 includes offset gates for M1 and M2. Byimplementing the layout 240 in this manner, improved body bias isprovided. For example, active region from the channel/gate all the wayto the body contact area can be provide with low or minimum parasitic.In certain implementations, silicide is used to provide lower parasiticpath/channel for the internal node snake construction.

FIG. 6A is a graph of one example of on resistance versus frequency.FIG. 6B is a graph of another example of on resistance versus frequency.

The graphs of FIGS. 6A and 6B depict on-state resistance (Ron) in Ohmsfor various implementations of RF switch layouts. The graphs depict lowRon, which aids in yielding good FOM.

FIG. 7A is a schematic diagram of one embodiment of an RF switch 300.The RF switch 300 includes a RF switch cell 301, a control circuit 302,a first gate resistor 303 a, and a second gate resistor 303 b.

The RF switch cell 301 includes transistors M1 and M2 in series betweenan RF input RF_(IN) and an RF output RF_(OUT). The RF switch cell 301can be implemented in accordance with any of the embodiments herein.

As shown in FIG. 7A, the control circuit 302 turns on or off the RFswitch cell 301 by controlling the gate of M1 through gate resistor 303a and by controlling the gate of M2 through gate resistor 303 b. Forexample, the control circuit 302 can output a control voltage set to avoltage level for turning on or off the RF switch cell 301 as desired.

FIG. 7B is a schematic diagram of another embodiment of an RF switch310. The RF switch 310 includes RF switch cells 301 a, 301 b, . . . 301n, a control circuit 302, first gate resistors 303 al, 303 b 1, . . .303 n 1, and second gate resistor 303 a 2, 303 b 2, . . . 303 n 2.

In comparison to the RF switch 300 of FIG. 7A, the RF switch 310 of FIG.7B includes multiple (any number n) RF switch cells in series forenhanced power handling capability. Any number of RF switch cells can beplaced in series for higher power handling.

FIG. 7C is a schematic diagram of another embodiment of an RF switch320. The RF switch 320 includes RF switch cells 301 a, 301 b, . . . 301n, a control circuit 302, and gate resistors 303 a, 303 b, . . . 303 n.

In comparison to the RF switch 310 of FIG. 7B, the RF switch 320 of FIG.7C shares a gate resistor for the gate of M1 and M2 of a given RF switchcell. Such a configuration can be suitable, for example, forimplementations such as that shown in FIG. 5A in which the gates of M1and M2 are shorted within the layout of a given cell.

FIG. 7D is a schematic diagram of one embodiment of a front-end system350. The front-end system 350 includes a power amplifier 351, a lownoise amplifier 352, an antenna 353, and a transmit/receive (T/R) switch354.

The T/R switch 354 includes a first series RF switch 361 between theoutput of the power amplifier 351 and the antenna 353, a second seriesRF switch 362 between the antenna 353 and the input of the low noiseamplifier 352, a first shunt RF switch 363 between the output of thepower amplifier 351 and ground, and a second shunt RF switch 364 betweenthe input of the low noise amplifier 352 and ground.

Any combination of the first series RF switch 361, the second series RFswitch 362, the first shunt RF switch 363, and/or the second shunt RFswitch 364 can be implemented using one or more RF switch cellsimplemented in accordance with the teachings herein.

FIG. 8 is a schematic diagram of one embodiment of a mobile device 800.The mobile device 800 includes a baseband system 801, a transceiver 802,a front-end system 803, antennas 804, a power management system 805, amemory 806, a user interface 807, and a battery 808.

The mobile device 800 can be used communicate using a wide variety ofcommunications technologies, including, but not limited to, 2G, 3G, 4G(including LTE, LTE-Advanced, and LTE-Advanced Pro), 5G NR, WLAN (forinstance, WiFi), WPAN (for instance, Bluetooth and ZigBee), WMAN (forinstance, WiMax), and/or GPS technologies.

The transceiver 802 generates RF signals for transmission and processesincoming RF signals received from the antennas 804. It will beunderstood that various functionalities associated with the transmissionand receiving of RF signals can be achieved by one or more componentsthat are collectively represented in FIG. 8 as the transceiver 802. Inone example, separate components (for instance, separate circuits ordies) can be provided for handling certain types of RF signals.

The front-end system 803 aids in conditioning signals transmitted toand/or received from the antennas 804. In the illustrated embodiment,the front-end system 803 includes antenna tuning circuitry 810, poweramplifiers (PAs) 811, low noise amplifiers (LNAs) 812, filters 813,switches 814, and signal splitting/combining circuitry 815. However,other implementations are possible. Any of the switches 814 can beimplemented in accordance with the teachings herein.

The front-end system 803 can provide a number of functionalities,including, but not limited to, amplifying signals for transmission,amplifying received signals, filtering signals, switching betweendifferent bands, switching between different power modes, switchingbetween transmission and receiving modes, duplexing of signals,multiplexing of signals (for instance, diplexing or triplexing), or somecombination thereof.

In certain implementations, the mobile device 800 supports carrieraggregation, thereby providing flexibility to increase peak data rates.Carrier aggregation can be used for both Frequency Division Duplexing(FDD) and Time Division Duplexing (TDD), and may be used to aggregate aplurality of carriers or channels. Carrier aggregation includescontiguous aggregation, in which contiguous carriers within the sameoperating frequency band are aggregated. Carrier aggregation can also benon-contiguous, and can include carriers separated in frequency within acommon band or in different bands.

The antennas 804 can include antennas used for a wide variety of typesof communications. For example, the antennas 804 can include antennasfor transmitting and/or receiving signals associated with a wide varietyof frequencies and communications standards.

In certain implementations, the antennas 804 support MIMO communicationsand/or switched diversity communications. For example, MIMOcommunications use multiple antennas for communicating multiple datastreams over a single radio frequency channel. MIMO communicationsbenefit from higher signal to noise ratio, improved coding, and/orreduced signal interference due to spatial multiplexing differences ofthe radio environment. Switched diversity refers to communications inwhich a particular antenna is selected for operation at a particulartime. For example, a switch can be used to select a particular antennafrom a group of antennas based on a variety of factors, such as anobserved bit error rate and/or a signal strength indicator.

The mobile device 800 can operate with beamforming in certainimplementations. For example, the front-end system 803 can includeamplifiers having controllable gain and phase shifters havingcontrollable phase to provide beam formation and directivity fortransmission and/or reception of signals using the antennas 804. Forexample, in the context of signal transmission, the amplitude and phasesof the transmit signals provided to the antennas 804 are controlled suchthat radiated signals from the antennas 804 combine using constructiveand destructive interference to generate an aggregate transmit signalexhibiting beam-like qualities with more signal strength propagating ina given direction. In the context of signal reception, the amplitude andphases are controlled such that more signal energy is received when thesignal is arriving to the antennas 804 from a particular direction. Incertain implementations, the antennas 804 include one or more arrays ofantenna elements to enhance beamforming.

The baseband system 801 is coupled to the user interface 807 tofacilitate processing of various user input and output (I/O), such asvoice and data. The baseband system 801 provides the transceiver 802with digital representations of transmit signals, which the transceiver802 processes to generate RF signals for transmission. The basebandsystem 801 also processes digital representations of received signalsprovided by the transceiver 802. As shown in FIG. 8 , the basebandsystem 801 is coupled to the memory 806 of facilitate operation of themobile device 800.

The memory 806 can be used for a wide variety of purposes, such asstoring data and/or instructions to facilitate the operation of themobile device 800 and/or to provide storage of user information.

The power management system 805 provides a number of power managementfunctions of the mobile device 800. In certain implementations, thepower management system 805 includes a PA supply control circuit thatcontrols the supply voltages of the power amplifiers 811. For example,the power management system 805 can be configured to change the supplyvoltage(s) provided to one or more of the power amplifiers 811 toimprove efficiency, such as power added efficiency (PAE).

As shown in FIG. 8 , the power management system 805 receives a batteryvoltage from the battery 808. The battery 808 can be any suitablebattery for use in the mobile device 800, including, for example, alithium-ion battery.

FIG. 9 is a schematic diagram of a power amplifier system 860 accordingto one embodiment. The illustrated power amplifier system 860 includes abaseband processor 841, a transmitter/observation receiver 842, a poweramplifier (PA) 843, a directional coupler 844, front-end circuitry 845,an antenna 846, a PA bias control circuit 847, and a PA supply controlcircuit 848. The illustrated transmitter/observation receiver 842includes an I/Q modulator 857, a mixer 858, and an analog-to-digitalconverter (ADC) 859. In certain implementations, thetransmitter/observation receiver 842 is incorporated into a transceiver.

The baseband processor 841 can be used to generate an in-phase (I)signal and a quadrature-phase (Q) signal, which can be used to representa sinusoidal wave or signal of a desired amplitude, frequency, andphase. For example, the I signal can be used to represent an in-phasecomponent of the sinusoidal wave and the Q signal can be used torepresent a quadrature-phase component of the sinusoidal wave, which canbe an equivalent representation of the sinusoidal wave. In certainimplementations, the I and Q signals can be provided to the I/Qmodulator 857 in a digital format. The baseband processor 841 can be anysuitable processor configured to process a baseband signal. Forinstance, the baseband processor 841 can include a digital signalprocessor, a microprocessor, a programmable core, or any combinationthereof. Moreover, in some implementations, two or more basebandprocessors 841 can be included in the power amplifier system 860.

The I/Q modulator 857 can be configured to receive the I and Q signalsfrom the baseband processor 841 and to process the I and Q signals togenerate an RF signal. For example, the I/Q modulator 857 can includedigital-to-analog converters (DACs) configured to convert the I and Qsignals into an analog format, mixers for upconverting the I and Qsignals to RF, and a signal combiner for combining the upconverted I andQ signals into an RF signal suitable for amplification by the poweramplifier 843. In certain implementations, the I/Q modulator 857 caninclude one or more filters configured to filter frequency content ofsignals processed therein.

The power amplifier 843 can receive the RF signal from the I/Q modulator857, and when enabled can provide an amplified RF signal to the antenna846 via the front-end circuitry 845. The power amplifier 843 can be apush-pull amplifier implemented in accordance with any of theembodiments herein.

The front-end circuitry 845 can be implemented in a wide variety ofways. In one example, the front-end circuitry 845 includes one or moreswitches, filters, duplexers, multiplexers, and/or other components. Anyof the switches of the front-end circuitry 845 can be implemented inaccordance with the teachings herein.

The directional coupler 844 senses an output signal of the poweramplifier 823. Additionally, the sensed output signal from thedirectional coupler 844 is provided to the mixer 858, which multipliesthe sensed output signal by a reference signal of a controlledfrequency. The mixer 858 operates to generate a downshifted signal bydownshifting the sensed output signal's frequency content. Thedownshifted signal can be provided to the ADC 859, which can convert thedownshifted signal to a digital format suitable for processing by thebaseband processor 841. Including a feedback path from the output of thepower amplifier 843 to the baseband processor 841 can provide a numberof advantages. For example, implementing the baseband processor 841 inthis manner can aid in providing power control, compensating fortransmitter impairments, and/or in performing digital pre-distortion(DPD). Although one example of a sensing path for a power amplifier isshown, other implementations are possible.

The PA supply control circuit 848 receives a power control signal fromthe baseband processor 841, and controls supply voltages of the poweramplifier 843. In the illustrated configuration, the PA supply controlcircuit 848 generates a first supply voltage V_(CC1) for powering aninput stage of the power amplifier 843 and a second supply voltageV_(CC2) for powering an output stage of the power amplifier 843. The PAsupply control circuit 848 can control the voltage level of the firstsupply voltage V_(CC1) and/or the second supply voltage V_(CC2) toenhance the power amplifier system's PAE.

The PA supply control circuit 848 can employ various power managementtechniques to change the voltage level of one or more of the supplyvoltages over time to improve the power amplifier's power addedefficiency (PAE), thereby reducing power dissipation.

One technique for improving efficiency of a power amplifier is averagepower tracking (APT), in which a DC-to-DC converter is used to generatea supply voltage for a power amplifier based on the power amplifier'saverage output power. Another technique for improving efficiency of apower amplifier is envelope tracking (ET), in which a supply voltage ofthe power amplifier is controlled in relation to the envelope of the RFsignal. Thus, when a voltage level of the envelope of the RF signalincreases the voltage level of the power amplifier's supply voltage canbe increased. Likewise, when the voltage level of the envelope of the RFsignal decreases the voltage level of the power amplifier's supplyvoltage can be decreased to reduce power consumption.

In certain configurations, the PA supply control circuit 848 is amulti-mode supply control circuit that can operate in multiple supplycontrol modes including an APT mode and an ET mode. For example, thepower control signal from the baseband processor 841 can instruct the PAsupply control circuit 848 to operate in a particular supply controlmode.

As shown in FIG. 9 , the PA bias control circuit 847 receives a biascontrol signal from the baseband processor 841, and generates biascontrol signals for the power amplifier 843. In the illustratedconfiguration, the bias control circuit 847 generates bias controlsignals for both an input stage of the power amplifier 843 and an outputstage of the power amplifier 843. However, other implementations arepossible.

FIG. 10A is a schematic diagram of one embodiment of a packaged module900 (also referred to herein as a radio frequency module). FIG. 10B is aschematic diagram of a cross-section of the packaged module 900 of FIG.10A taken along the lines 10B-10B.

The packaged module 900 includes radio frequency components 901, asemiconductor die 902, surface mount devices 903, wirebonds 908, apackage substrate 920, and an encapsulation structure 940. The packagesubstrate 920 includes pads 906 formed from conductors disposed therein.Additionally, the semiconductor die 902 includes pins or pads 904, andthe wirebonds 908 have been used to connect the pads 904 of the die 902to the pads 906 of the package substrate 920.

The semiconductor die 902 includes a radio frequency switch 945 and oneor more front end circuit blocks 946 that are connected to the radiofrequency switch 945. The semiconductor die 902 can be implemented inaccordance with any of the features disclosed herein.

The packaging substrate 920 can be configured to receive a plurality ofcomponents such as radio frequency components 901, the semiconductor die902 and the surface mount devices 903, which can include, for example,surface mount capacitors and/or inductors. In one implementation, theradio frequency components 901 include integrated passive devices(IPDs).

As shown in FIG. 10B, the packaged module 900 is shown to include aplurality of contact pads 932 disposed on the side of the packagedmodule 900 opposite the side used to mount the semiconductor die 902.Configuring the packaged module 900 in this manner can aid in connectingthe packaged module 900 to a circuit board, such as a phone board of amobile device. The example contact pads 932 can be configured to provideradio frequency signals, bias signals, and/or power (for example, apower supply voltage and ground) to the semiconductor die 902 and/orother components. As shown in FIG. 10B, the electrical connectionsbetween the contact pads 932 and the semiconductor die 902 can befacilitated by connections 933 through the package substrate 920. Theconnections 933 can represent electrical paths formed through thepackage substrate 920, such as connections associated with vias andconductors of a multilayer laminated package substrate.

In some embodiments, the packaged module 900 can also include one ormore packaging structures to, for example, provide protection and/orfacilitate handling. Such a packaging structure can include overmold orencapsulation structure 940 formed over the packaging substrate 920 andthe components and die(s) disposed thereon.

It will be understood that although the packaged module 900 is describedin the context of electrical connections based on wirebonds, one or morefeatures of the present disclosure can also be implemented in otherpackaging configurations, including, for example, flip-chipconfigurations.

Applications

The principles and advantages of the embodiments herein can be used forany other systems or apparatus that have needs for RF switches. Examplesof such apparatus include RF communication systems such as mobilephones, tablets, base stations, network access points, customer-premisesequipment (CPE), laptops, and wearable electronics. Thus, the RFswitches herein can be included in various electronic devices,including, but not limited to, consumer electronic products.

CONCLUSION

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Likewise, the word “connected”, as generally used herein, refers to twoor more elements that may be either directly connected, or connected byway of one or more intermediate elements. Additionally, the words“herein,” “above,” “below,” and words of similar import, when used inthis application, shall refer to this application as a whole and not toany particular portions of this application. Where the context permits,words in the above Detailed Description using the singular or pluralnumber may also include the plural or singular number respectively. Theword “or” in reference to a list of two or more items, that word coversall of the following interpretations of the word: any of the items inthe list, all of the items in the list, and any combination of the itemsin the list.

Moreover, conditional language used herein, such as, among others,“may,” “could,” “might,” “can,” “e.g.,” “for example,” “such as” and thelike, unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/orstates are included or are to be performed in any particular embodiment.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. A radio frequency switch comprising: a firsttransistor gate structure including a first gate connection extending inparallel with a first edge of an active region, and a first transistorgate extending from the first gate connection over the first edge of theactive region; a second transistor gate structure including a secondgate connection extending in parallel with a second edge of the activeregion opposite the first edge, and a second transistor gate extendingfrom the second gate connection over the second edge of the activeregion; a radio frequency switch input including a first source/drainconnection extending in parallel to the first transistor gate andcontacting the active region; and a radio frequency switch outputincluding a second source/drain connection extending in parallel to thesecond transistor gate and contacting the active region, the firsttransistor gate and the second transistor gate positioned between thefirst source/drain connection and the second source/drain connection. 2.The radio frequency switch of claim 1 wherein the first source/drainconnection does not reach the second edge of the active region, and thesecond source/drain connection does not reach the first edge of theactive region.
 3. The radio frequency switch of claim 1 wherein thefirst gate connection, the first transistor gate, the second gateconnection, and the second transistor gate are formed of polysilicon. 4.The radio frequency switch of claim 1 wherein the active region isrectangular.
 5. The radio frequency switch of claim 1 wherein the activeregion includes a first rectangular region and a second rectangularregion, the first rectangular region abutting but offset from the secondrectangular region.
 6. The radio frequency switch of claim 5 wherein thefirst transistor gate extends over the first rectangular region, and thesecond transistor gate extends over the second rectangular region. 7.The radio frequency switch of claim 1 further comprising an internaldrain/source bias region extending in parallel to the second edge of theactive region, the internal drain/source bias region contacting theactive region between the first transistor gate and the secondtransistor gate.
 8. The radio frequency switch of claim 1 wherein theactive region is formed in a semiconductor, the radio frequency switchfurther including a body contact region that contacts the semiconductoradjacent to the first edge of the active region.
 9. The radio frequencyswitch of claim 8 wherein the body contact region includes a pluralityof body contacts bridged by metal.
 10. The radio frequency switch ofclaim 8 wherein a body contact is present only on one side of the activeregion.
 11. A mobile device comprising: an antenna; and a front-endsystem coupled to the antenna and including a radio frequency switch,the radio frequency switch including a first transistor gate structurethat includes a first gate connection extending in parallel with a firstedge of an active region and a first transistor gate extending from thefirst gate connection over the first edge of the active region, a secondtransistor gate structure that includes a second gate connectionextending in parallel with a second edge of the active region oppositethe first edge and a second transistor gate extending from the secondgate connection over the second edge of the active region, a radiofrequency switch input that includes a first source/drain connectionextending in parallel to the first transistor gate and contacting theactive region, and a radio frequency switch output that includes asecond source/drain connection extending in parallel to the secondtransistor gate and contacting the active region, the first transistorgate and the second transistor gate positioned between the firstsource/drain connection and the second source/drain connection.
 12. Themobile device of claim 11 wherein the front-end system further includesa power amplifier having an output connected to the radio frequencyswitch input.
 13. The mobile device of claim 11 wherein the front-endsystem further includes a low noise amplifier having an input connectedto the radio frequency switch output.
 14. A packaged module comprising:a package substrate; and a semiconductor die attached to the packagesubstrate and including a radio frequency switch formed thereon, theradio frequency switch including a first transistor gate structure thatincludes a first gate connection extending in parallel with a first edgeof an active region and a first transistor gate extending from the firstgate connection over the first edge of the active region, a secondtransistor gate structure that includes a second gate connectionextending in parallel with a second edge of the active region oppositethe first edge and a second transistor gate extending from the secondgate connection over the second edge of the active region, a radiofrequency switch input that includes a first source/drain connectionextending in parallel to the first transistor gate and contacting theactive region, and a radio frequency switch output that includes asecond source/drain connection extending in parallel to the secondtransistor gate and contacting the active region, the first transistorgate and the second transistor gate positioned between the firstsource/drain connection and the second source/drain connection.
 15. Thepackaged module of claim 14 wherein the first source/drain connectiondoes not reach the second edge of the active region, and the secondsource/drain connection does not reach the first edge of the activeregion.
 16. The packaged module of claim 14 wherein the first gateconnection, the first transistor gate, the second gate connection, andthe second transistor gate are formed of polysilicon.
 17. The packagedmodule of claim 14 wherein the active region is rectangular.
 18. Thepackaged module of claim 14 wherein the active region includes a firstrectangular region and a second rectangular region, the firstrectangular region abutting but offset from the second rectangularregion.
 19. The packaged module of claim 18 wherein the first transistorgate extends over the first rectangular region, and the secondtransistor gate extends over the second rectangular region.
 20. Thepackaged module of claim 14 further comprising an internal drain/sourcebias region extending in parallel to the second edge of the activeregion, the internal drain/source bias region contacting the activeregion between the first transistor gate and the second transistor gate.